Piston valve with mid-position bypass



Feb. 22, 1938. BOEHLE 2,109,162

' PISTON VALVE WITH MID POSITION BYPASS Filed Feb. 15, 1935' 5' Sheets-Sheet 1 Feb. 22, 1938. F. BOEHLE 2,109,162

PISTON VALVE WITH MID POSITION BYPASS Filed Feb. 15, 1935 5 Sheets-Sheet 2 EXHAUST Jn/u FRIEDEL BOEHLE,

Feb. 22, 1938. F. BOEHLE PISTON Filed Feb. 15, 1935 VALVE WITH MID POSITION BYPASS 3 Sheets-Sheet 3 EXHAUST PUMP Muir t PUMP 57 Jrvuwm FRIEDEL BOEHLE,

Patented Feb. 22, 1938 UNITED- STATES PISTON VALVE WITH MID-POSITION BYPASS Friedel Boehle, Mount Gilead, Ohio, asslgnor to The Hydraulic Press Corporation, Inc., Wilmington, DeL, a corporation of Delaware Application February 15, 1935, Serial No. 6,650

10 Claims.

This invention relates to hydraulic machinery, and in particular to valves for controlling the operation of such machinery.

One object of my invention is to provide a piston type valve having spaced heads, and a mid-position by-pass arrangement.

Another object is to provide a piston type valve having at least four operating positions, one of which positions provides a by-passing of the pump, together with a throttling efiect maintaining a slight back pressure in the return side of the press. sufiicient to counterbalance the weight of the plunger and hold the platen in a position of rest.

Another object is to provide a valve for controlling hydraulic machinery, said valve consisting of a pair of spaced heads reciprocating in a bore'having a plurality of chambers, this bore being provided with a central by-pass memher so arranged that a slight motion of one of the heads will close one side of the by-pass to permit the other side to be opened to pressure from the pump.

Another object is to provide a piston type valve having a casing with a cylindrical bore, and a plurality of spaced chambers, and a valve plunger with a plurality of spaced solid heads, reciprocable in this bore, the casing having in the mid-position of the bore a central member arranged to pass fluid from either side or both, according to the respective positions of the valve heads.

Another object is'to provide a piston type valve of the kind just described, wherein both of the cylinder connections may be closed off. simultaneously while the pump is allowed to by-pass freely through the central by-pass member of the valve.

Another pbject is to provide a hydraulic circuit containing a four-position piston type valve and a press controlled thereby, this valve having a central by-pass member so arranged that in one position it by-passes the major portion of the pump discharge into the exhaust line but by a throttling efiect maintains sufficient pressure on the return side of the plunger to counterbalance the weight of the moving parts, and maintain the plunger in a position of rest.

50 Referring to the drawings:

Figure 1 is a diagrammatic side elevation, partly in section, of'a typical hydraulic circuit, in which the valve of my invention may be used.

Figure 2 is a central longitudinal section 55 through the valve of my invention, showing the valve in its neutral or complete by-passing position.-

Figure 3 is a. view similar to Figure 2, but with the valve in a position to cause a return stroke of the pressplunger. 5

Figure 4 is a view similar to Figures 2' and 3, but with the valve in a position to cause the press plunger to make a forward stroke.

Figure 5 is a view similar to Figures 2, 3, and 4, but with the valve in the partial by-passing 10 position so that the pump discharge is by-passed, but a throttling effect is produced which maintains a suflicient pressure in the return side of the press cylinder to counterbalance the weight of the plunger and maintain it in a position of 1 rest.

Figure 6 is a cross section taken along the line 6-6 in Figure 2.

Hydraulic circuit for valve Referring to the drawings in detail, Figure 1 shows a circuit chosen for purposes of exemplifl cation only, in which the valve of my invention, generally designated l0, may be employed. In this circuit is also shown a fluid tank H, from 25 which the pipe line I! runs to the suction side of the pump i3, from the discharge side of which the pressure pipe ll communicates with the central port i5 of the valve l0.

From the upper port l6 of the valve III the 30 pipe line l1 runs to the entrance port l8 of the press cylinder l9, above the piston head 20 of the press plunger 2|. The port l8 opens into the chamber 22, the admission of pressure fluid to which causes the press plunger M to move 35 downward and make a working stroke. A platen 23 is attached to the lower end of the plunger 2 I.

From the lower port 24 of the valve .I0 the pipe line 25 runs to the port 26, opening into the chamber 21 beneath the piston head 20, the ad- 40 mission of pressure to which causesthe plunger 2| to execute a return stroke. From the central port 28 on the opposite side of the valve ill from the ports I5, l6 and 24 the exhaust pipe line 29 runs back to the fluid tank H. The ports I6 and 24 thus act as service ports for the transmission of fluid to and from the hydraulic machine to which the valve"! is connected.

The cylinder is of the press is connected by the strain rods 30 to the bed plate 3i of the press. Mounted onthe frame thus constructed, as on one of the strain rods 30, is the operating lever 32 having the operating shaft 33, terminating in a yoked crank portion 34. The frame of' the press is provided with extension arms 35 and 36,-

having bores through which passes the valve control rod 31, the latter also passing between the arms of the yoked crank portion 34.

A spring 38, engaging a collar 33 fixed on the valve control rod 31, urges the latter into a downward position, the opposite end of the spring 36 engaging the frame arm 36. A second fixed collar 40 on the valve control rod 31 is adjustably arranged to be engaged by the yoked crank portion 34 and be moved up or down thereby, according to the motion given the control lever 32 through the operating shaft 33.

The valve controlrod 31 also carries a fixed collar 4| adapted to be engaged by an arm 42 extending laterally from the platen 23 when the platen reaches a predetermined point in its upward or return stroke. This motion causes the valve control rod 31 to move upward, carrying with it the internal members of the valve ID, as will subsequently appear. Another adjustable collar 66 on the lower end of the valve control rbd 31 limits the downward movement of the latter by engaging the frame arm 35.

The positions of the collars 39, 40, 4|, and 66 may be adjusted along the rod 31 by loosening the set screws thereof in order to provide for the proper timing of the valve.

Valve construction The valve ||l of my invention (Figures 2 to 5,

inclusive), consists of a casing 43 having alongitudinal bore 44 therethrough, the ends of which are closed by the plugs 45, the plugs having the packings 46 and glands 41 for tightening the same. A bore 48 through each plug 45 and gland 41 serves to permit the reciprocation of the valve rod 43, the latter being, in effect, a continuation of the valve control rod 31 (Figure 1). Leakage between the valve rod 49 and the bore 46 is pre- 40 vented by the packing 46, previously described.

The valve bore 44 is provided with chambers 50, 5|, 52, 53, and 54, arranged successively along the bore 44. The central chamber 52 is further subdivided into the sub-chambers 55 and 56, re-

spectively, by the mid-position by-pass member 51. The latter is of annular construction, with passages 56 and 53 opening into a central chamber 6|l'thereof from the sub-chambers 55 and 56, respectively. The chambers 66, 55, and 54 open 50 into the exhaust manifold 6| of the casing 43, the discharge thereof passing outward through the exhaust port 26 by way of the pipe line 23 to the tank I I. The chambers 5| and 53, however, communicate with the lower and upper ports 24 and 55 I6, respectively, of the valve casing 43. Finally, the central chamber 52 opens into the pressure port |5 connected by the pipe line l4 to the pressure side of the pump |3.

60 The valve rod 48 is provided with spaced heads 62 and 63, respectively, these being of such length as to cover and uncover the various chambers in the manner described below, according to the motion of the valve rod and the valve control 5 rod 31. The spaced heads 62 and 63 areconnected by the neck 64, which forms, in eflect, a slightly enlarged portion of the valve rod 49.

in Figure 1. It will be understood, however, that .this circuit is diagrammatic and that other cir- I 75 cuits may be substituted without departing from stroke.

the spirit of my inventon as expressed in the appended claims.

To start the press in operation, in order to perform a working stroke, the control lever 32 is manipulated so as to raise the valve control rod 31 to its uppermost position against the urge of the spring 36 (Figure 1). At the same time the spaced heads 62 and 63 move upward to the uppermost positions shown in Figure 4. When the heads are in this position the pressure discharge of the pump passes along the pipe l4, through the port l5, into the central chamber 52, thence through the sub-chamber 56, the chamber 53, the port IS, the pipe line H and the port=|3 into the chamber 22 of the press cylinder l3 above the plston'head 26 thereof. This causes the pitton head and the plunger 2| to move downward, executing a pressing stroke with the platen 23. v

The platen 23 moves downward until it encounters the work and completes its working The working stroke may be terminated in any desired manner, either manually by manipulating the hand lever 32, by a pressure-responsive reversal, or by positionally-responsive means, such as electrical switches or stops on the valve rod 31. These devices are well known to thou skilled in the art, and require no further description. For present purposes it' will be assumed that the manual operation is followed. J

Accordingly, when the platen has proceeded downward to the desired extent, the hand lever 32 is released. This releases the collar 45 so that the valve control'rod 31 is urged down by the spring 38 into its lowermost position (Figure 3). In this position the spaced heads 62 and 63 also come to rest in their lowermost positions, permitting the discharge of the pump to pass from the central chamber 52 by way of the sub-chamber 55, the chamber 5|, the port 24, the pipe line and the port 26 into the chamber 21 beneath the piston head 20 of the press cylinder l3, lifting the plunger 2| and causing a return stroke of the platen 23 to occur.

The platen 23 continues to move upward in this manner until the end of the platen arm 42 en? gages the collar 4|, lifting the valve control rod 31, and with it the valve heads 62 and 53 into the partial by-pass position shown in Figure 5. In this position the valve heads 62 and 63 occupy aslightly higher position than in the return position shown in Figure 3.

In the partial by-pass position (Figure 5), the

discharge from the pump passes from the chamber 52, through the sub-chamber and the central by-pass chamber into the exhaust manifold 6|, thence by way of the exhaust port 23 and the exhaust line 23 to the tank I The throttling effect between the edges of the valve piston head 63 and the central by-pass chamber 66 r causes a back pressure to be set up which is transmitted backward through the sub-chamber 56, the chamber 5|, the port 24, the pipe line 25' and the port 26 into the chamber 21 below the piston head 20. The positions of the collars 33 and 45, as well as 4| are adjusted until the back pressure passing into the return chamber 21 is sufllcient to sustain the weight of the piston 23 and its associated moving parts in a position of rest.

If it is desired to maintain the platen in a position where the pressure is retained upon the work the valve heads 62 and 63 may be moved into the full by-pass position shown in Figure 2. In this position the fluid on both the return side 21 and the forward side 22 of the piston 25 is entirely out oif from the valve so that the piston 20 remains immovable and with it the platen 23. The full discharge of the pump then passes through "the port l5, the-central chamber 52, the

. sub-chambers 55 and 56, the central by-pass chamber 60, the exhaust manifold 6 l, the exhaust port 28 'and'the exhaust line 29, into the fluid tank II. In this position no fluid is allowed to enter-or leave either side of the cylinder l9 so that the piston 20 and platen 23 remain immovable. This position is obtained by a suitable manipulation of the hand lever 32.

It will be obvious that the valve heads 62 and 63 may be raised :into a second partial by-pass position having a similar effect to the position shown in Figure 5. In this second partial bypass position, however, the valve heads 62 and 63 will be located at approximately the same distances below the upper end of the valve chamber as they are above the bottom shown in Figure 5.

Thus it will be seen that I have provided a valve which is capable of operation in five different positions, four of which have been completely disclosed above. It will be furthermore apparent from the foregoing'that the valve in its central position may assume a complete by-passing position, allowing none of the fluid to enter or leave either side of the cylinder, or other hydraulic machine controlled thereby. It will be furthermore apparent that the valve may be' caused to assume a partial by-pass position so that the pump discharge will be by-passed, but a back pressure produced by a throttling effect sufiicient to maintain the press plunger in a state of rest without exerting any force upon the workpiece, such as at the end of the return stroke.

It will be further understood that in place of the double-acting piston shown I may employ a single-acting pressing plunger with pull-back plungers, these being connected to the valve in a similar manner.

I desire to comprehend within my invention such modifications as may be embraced within my claims and the scope of my invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. A valve for controlling hydraulic circuits comprising a casing having a bore with a plurality of chambers, said casing having an inlet and an outlet and a pair of service ports communicating with said chambers, and a valve rod with spaced heads reciprocable in said bore, one of said chambers being centrally located in said casing, said casing having a bored projecting portion extending into said central chamber, said valve rod and said heads being adapted in one position to cut off communication simultaneously between said inlet and said service ports while by-passing the fluid from said inlet to said outlet through said central chamber past said projecting portion.

2. A valve for controlling hydraulic circuits comprising a casing having a bore with a plurality of chambers, said casing. having an inlet and an outlet and a pair of service ports communicating with said chambers, and a valve rod with spaced heads reciprocable in said bore, one of said chambers being centrally located in said casing, said casing having a bored projecting portion extending into said central chamber, said bored projecting portion being arranged to subdivide said central chamber into a plurality of sub-chambers, said valve rod and said heads being adapted in one position to cut off communication simultaneously between said inlet and said service ports while by-passing the fluid from said inlet "to 'said outlet through said central chamber past said projecting portion.

3. A valve for controlling hydraulic circuits comprising a casing having a bore with a plurality of chambers,'said casing having an inlet and'an outlet and a pair of service port-s communicating with said chambers, andxa valve rod with spaced heads reciprocable in said bore, one of said chambers being centrally located in said casing, said casing having a bored'projecting portion extending into said central chamber, said bored projecting portion being arranged to subdivide saidcentral chamber into a central subchamber and side sub-chambers communicating therewith, said'valve 'rod and said heads being adapted in one position to cut off communication simultaneously between said inlet and said service ports while by-passing the fluid from said inlet to said outlet through said central chamber past said of service ports communicating with said chamhers, and a valve rod with spaced heads reciprocable in said bore, said casing having a bored projecting portion extending into said central chamber, said valve rod and said heads being adapted in one position to cut of)? communication simultaneously between said inlet and said service ports while by-passing the fluid from said inlet to said outlet through said central chamber past said projecting portion.

5. A valve for controlling hydraulic circuits comprising a casing having a bore, said bore being divided into a central chamber and end chambers with intermediate chambers therebetween, said casing having an inlet and an outlet and a pair of service ports communicating with said chambers, and a valve rod with spaced heads reciprocable in said bore, said casing having a bored projecting portion extending into said cen tral chamber, said bored projecting portion being arranged to subdivide said central chamber into a plurality of sub-chambers, said valve rod and said heads being adapted in one position to cut oil communication simultaneously between said inlet and said service ports while by-passing the fluid from said inlet to said outlet through said central chamber past said projecting portion.

6. A valve for controlling hydraulic circuits comprising a casing having a bore, said bore being divided into a central chamber and end chambers with intermediate chambers therebetween, said casing having an inlet and an outlet and a pair of service ports communicating with said chambers, and a valve rod with spaced heads reciprocable in said bore, said casing having a bored projecting portion extending into said central chamber, said bored projecting portion being arranged to subdivide said centralchamber into a central sub-chamber and side sub-chambers communicating therewith, said valve rod and said heads being adapted in one position to cut oil. communication simultaneously between said inlet and said service ports while by-passing the fluid from said inlet to said outlet through said central chamber past said projecting portion.

7. A valve for controlling hydraulic circuits comprising a casing having a bore, said bore.

having a central chamber, another chamber on each side oi said central chamber in spaced relationship therewith, said central chamber having a bored projecting portion 01' said casing extending therein, said casing having an inlet and an outlet and a pair 01' service ports communicating with said chambers," and a valve rod with spaced heads reciprocable in said bore and through said bored projecting portion, said valve rod and said heads being adapted in one position to cut 03 communication simultaneously between said inlet and said service ports while by-passing the fluid from said inlet to said outlet through said central chamber past said projecting portion.

8. A hydraulically-operated machine system comprising a plunger, a cylinder therefor having hydraulic connections opening from opposite sides oi said plunger, 9. source or pressure fluid, a valve with a valve casing arranged to control the supply of pressure fluid from said source to said cylinder, said valve casing having a,bore with a central chamber, and intermediate chambers in spaced relationship on either side thereof, said casing having an inlet and an outlet and a pair of service ports communicating with said chambers, said central chamber having a bored pro-r jecting portion of said casing extending thereinto, said valve having a valve rod with spaced heads rcciprocable in said bore, and mechanism connecting said plunger and said valve rod, said valve rod and'heads being adapted in one position to cut of! communication simultaneously between ,said intermediate chambers and said central chamber while by-passing the discharge from said inlet through said central chamber past said projecting portion into said outlet.

9. A hydraulically-operated machine system comprising a plunger, a cylinder therefor having hydraulic connections opening from opposite sides of said plunger, a source of pressure fluid, a valve 40 with a valve casing arranged to control the supply of pressure fluid from said source to said cylinder, said valve casing having a bore divided into a central chamber and end chambers with intermediate chambers therebetween, said casing having an inlet and an outlet and a pair of service ports communicating with said chambers.

said central chamber having a bored projecting portion of said casing extending therein, said valve having a valve rod with spaced heads reciprocable in said bore, and mechanism interconnecting said plunger and said valve rod, said valve rod and heads being adapted in one position to cut oil communication simultaneously between said intermediate chambers and said central chamber while by-passing the discharge irom said inlet through said central chamber past said projecting portion into said outlet.

10. A hydraulically-operated machine system comprising a plunger, 9. cylinder therefor having hydraulic connections opening from oppomie sides or said plunger, a source of pressure fluid, a valve with a valve casing arranged to control the supply of pressure fluid from said source to said cylinder, said valve casing having a bore divided into a central chamber and end chambers with intermediate chambers therebetween, said casing having an inlet and an outlet and a pair of service ports communicating with said chambers, said central chamber having a bored projecting portion of said casing extending therein, said valve having a valve rod with spaced heads reciprocable in said bore, and mechanism interconnecting said plunger and said valve rod, said valve rod and heads beingadapted in one position to cut oil communication simultaneoimly between said intermediate chambers and said central chamber while by-passing the discharge from said inlet through said central chamber past said projecting portion into said outlet, said boned projecting portion being arranged to subdivide said central chamber into a central sub-chamber and side sub-chambers.

FRIEDEL BOEHLE. 

